1999 Ford Expedition EB 4WD 5.4L 200K, Started to sputter and shutters under load / heavy acceleration increasing RPM's, low or high RPM's with more than 1/3 + peddle. Normal driving up to 1/3 peddle and under 2K RPM's NO sputter or shutter. Initially told misfire Bank 1 & 2, suggestion was to replace COP's and injector O-rings. Replaced all spark plugs, COP's and injectors. Starts instantaneously now and more responsive but still shutters and sputters under load. Suggestion to replace TPS, MAF and fuel filter since it had 200K on it and nothing had been replaced since new so I replaced all. Still shutters and sputters but now notice it runs a little rough at idle and the exhaust though it sounds the same smells weird not like gas just something I've never smelled before. Suggestion of possible vac leak, have sprayed carb cleaner, brake cleaner and starter fluid all around can't fine anything, Starts immediately cold or hot, cold IAC has it at 980 RPM's then settles to 600 RPM's. Never surges, Never Dies, Stays Running. Drove around for about an hour trying to get it to throw a code, it threw P1132 and P1152, Sensor 1 for banks 1 & 2 , LACK OF H2OS11-NOT SWITCHING - RICH assuming this means LEAN (no O2) condition from what i've read. Suggestion was test the fuel pressure and regulator. 30 psi at the rail, 35 psi with new fuel filter engine running. Removed vac hose from regulator jumps to 40 psi. Engine off, ignition off, psi drops to 0 in a couple of minutes. Never holds pressure once off. Q: shouldn't line hold pressure within 5psi when pump is off? Also, Is the fuel pump working just not enough when fuel demand increases.

 

Sounds like both are bad. A bad cat would explain the weird, (rotten eggs) smell. Bad fuel pump explains the low fuel pressure. Now losing pressure so fast sounds like possibly leaky injector(s). I would have an exhaust pressure test done, and inspect or just replace all of your injectors considering the mileage that they have on them.

 

Being that you have already replaced all the injectors, I'd suspect the regulator - it shouldn't bleed down that fast. If you are getting 35 psi with the engine running, I'd think the fuel pump is probably okay, you would have to do a flow test on it to make sure. That pressure is within spec. It's possible both upstream O2's are bad, but not very likely. If the exhaust smells weird the cats are probably plugged, a muffler shop can test them.

 

Thanks glc, would you suggest return pinch test for regulator? I'm not sure if removing the vac hose is enough since its part of the driver side rail. I'll track down a reputable muffler shop today and see if they can test the cats for me. If not, I may need to do a heat test or unbolt the the casts from the header one at a time to see if shutter stips?

 

Afterthought, wouldn't the fuel pressure go up if the regulator was bad? wouldn't the pressure stay constant if the vac hose is removed? When I remove the vac hose the pressure goes to 40 which I think is max spec.? Thoughts?